THEORIES OF WEAR AND LOOSENING IN HIP PROSTHESES - WEAR-INDUCED LOOSENING VS LOOSENING-INDUCED WEAR - A REVIEW

The observation of periprosthetic granulomas containing wear debris ar ound apparently well-fixed as well as around loose-fitting prosthetic components has led to the development of the hypothesis of wear-induce d loosening. However, the hypothesis of wear-induced loosening can nei ther explain the rapid early prosthetic migration detected by roentgen stereophotogrammetry nor the epidemiology of clinical failure without supplementary ad hoc-assumptions. By contrast, apart from explaining the rapid early prosthetic migration detected by roentgen stereophotog rammetry, the theory of early loosening can explain the development of wear granulomas as well as to a great extent the epidemiology of clin ical failure.